Obesity
appears to be associated with an increased risk of depression, and
depression also appears associated with an increased risk of developing
obesity, according to a meta-analysis of previously published studies
in the March issue of Archives of General Psychiatry, one of the
JAMA/Archives journals.

"Both
depression and obesity are widely spread problems with major public
health implications," the authors write as background information in
the article. "Because of the high prevalence of both depression and
obesity, and the fact that they both carry an increased risk for
cardiovascular disease, a potential association between depression and
obesity has been presumed and repeatedly been examined." Understanding
the relationship between the two conditions over time could help
improve prevention and intervention strategies.

Floriana
S. Luppino, M.D., of Leiden University Medical Center and GGZ
Rivierduinen, Leiden, the Netherlands, and colleagues analyzed the
results of 15 previously published studies involving 58,745
participants that examined the longitudinal (over time) relationship
between depression and overweight or obesity.

"We
found bidirectional associations between depression and obesity: obese
persons had a 55 percent increased risk of developing depression over
time, whereas depressed persons had a 58 percent increased risk of
becoming obese," the authors write. "The association between depression
and obesity was stronger than the association between depression and
overweight, which reflects a dose-response gradient."

Sub-analyses
demonstrated that the association between obesity and later depression
was more pronounced among Americans than among Europeans, and stronger
for diagnosed depressive disorder compared with depressive symptoms.

Evidence
of a biological link between overweight, obesity and depression remains
uncertain and complex, but several theories have been proposed, the
authors note. Obesity may be considered an inflammatory state, and
inflammation is associated with the risk of depression. Because
thinness is considered a beauty ideal in both the United States and
Europe, being overweight or obese may contribute to body
dissatisfaction and low self-esteem that places individuals at risk for
depression. Conversely, depression may increase weight over time
through interference with the endocrine system or the adverse effects
of antidepressant medication.

The
findings are important for clinical practice, the authors note.
"Because weight gain appears to be a late consequence of depression,
care providers should be aware that within depressive patients weight
should be monitored. In overweight or obese patients, mood should be
monitored. This awareness could lead to prevention, early detection and
co-treatment for the ones at risk, which could ultimately reduce the
burden of both conditions," they conclude.